Mp3 audio format

[bobbybans 0]

I know, everybody heard for this audio format, but I am interested what is the difference between mp3 and mp3pro and lame mp3.I just can't see the difference between those mp3 audio formats. And another thing is there any difference between stereo sound and joint stereo sound coded in one of these mp3 audio formats. I know that mono has just 1 channel and stereo has 2 channels, so I am asking what is joint stereo. How many channels are there? I would be very appreciate to someone who knows any difference.Regards.

Edited April 16, 2008 by bobbybans (see edit history)

[Starchaser 0]

Well what is mp3 we all know well enough. mp3pro supposed to be an evolution of mp3, by using different algorithms, it was supposed to be able to offer same bitrates as mp3, but take up less space, unfortunately, it seems mp3pro failed, as i haven't heard about it in a very long time. Even the player industry didn't include support for this format, exept 1 company, but they droped it as well. Now i might be wrong, but LAME mp3 and mp3 is originaly the same thing, because LAME is just the encoder used to convert audio to mp3.

Now regarding your question about stereo and joint stereo. As you said, stereo offers more than one channel, which enables us to make an impression that sound is comming from different directions, as in case of natural hearing. But stereo doesn't offer just 2 channels, it offers 2 or more channels. Would we have 5.1 audio sistems if it only offered 2 channels?

Joint stereo. I will paste a small clip of info from wikipedia on this, as i am not a specialist in this field, i have basic knowledge, so to make shure i get this right, here is a small clip from Wikipedia.

'Joint frequency encoding is an encoding technique used in audio data compression to reduce the data rate.The idea is to merge a given frequency range of multiple sound channels together so that the resulting encoding will preserve the sound information of that range not as a bundle of separate channels but as one homogenous data stream. This will naturally destroy the original channel separation for good, as the information cannot be accurately reconstructed, but this process will greatly lessen the amount of required storage space. It should be noted that only some forms of joint stereo use the joint frequency encoding technique, such as intensity stereo coding.'

Just to clarify if any part is confusing to anyone. The general idea behind this is to merge identical information from left and right chanel in to one, in places where it is possible, thus saving space. It is not continuos, meaning as soon as 'stereo effects' start, like car zooming on left, joint stereo ends, and you continue to hear only the left speaker emmiting sound - the passing cars roar, and starts only when sound on both channels becomes identical again, like a conversation between actors.
Edited September 27, 2008 by Starchaser (see edit history)